text: /*******************************************************************************
   * Copyright (c) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included
   * in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
   * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
   * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
   * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
   * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
   * OTHER DEALINGS IN THE SOFTWARE.
   *
   * Except as contained in this notice, the name of Maxim Integrated
   * Products, Inc. shall not be used except as stated in the Maxim Integrated
   * Products, Inc. Branding Policy.
   *
   * The mere transfer of this software does not imply any licenses
   * of trade secrets, proprietary technology, copyrights, patents,
   * trademarks, maskwork rights, or any other form of intellectual
   * property whatsoever. Maxim Integrated Products, Inc. retains all
   * ownership rights.
   *******************************************************************************
   */
  
  #include "mbed_assert.h"
  #include "i2c_api.h"
  
  #if DEVICE_I2C
  
  #include "i2cm_regs.h"
  #include "i2cm.h"
  #include "pinmap.h"
  #include "PeripheralPins.h"
  
  #ifndef MXC_I2CM_RX_TIMEOUT
  #define MXC_I2CM_RX_TIMEOUT     0x5000
  #endif
  
  #define MBED_NAK     0
  #define MBED_ACK     1
  #define MBED_TIMEOUT 2
  
  //******************************************************************************
  void i2c_init(i2c_t *obj, PinName sda, PinName scl)
  {
      // SDA and SCL must map to same peripheral instance
      I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA);
      I2CName i2c_scl = (I2CName)pinmap_peripheral(scl, PinMap_I2C_SCL);
      mxc_i2cm_regs_t *i2c = (mxc_i2cm_regs_t*)pinmap_merge(i2c_sda, i2c_scl);
      MBED_ASSERT((int)i2c != NC);
  
      obj->i2c = i2c;
      obj->fifo = MXC_I2CM_GET_FIFO(MXC_I2CM_GET_IDX(i2c));
      obj->start_pending = 0;
  
      // Merge pin function requests for use with CMSIS init func
      ioman_req_t io_req;
      pin_function_t *pin_func;
      pin_func = (pin_function_t *)pinmap_find_function(sda, PinMap_I2C_SDA);
      io_req.value  = pin_func->req_val;
      pin_func = (pin_function_t *)pinmap_find_function(scl, PinMap_I2C_SCL);
      io_req.value |= pin_func->req_val;
  
      obj->sys_cfg.io_cfg.req_reg = pin_func->reg_req;
      obj->sys_cfg.io_cfg.ack_reg = pin_func->reg_ack;
      obj->sys_cfg.io_cfg.req_val = io_req;
      obj->sys_cfg.clk_scale = CLKMAN_SCALE_DIV_1;
  
      I2CM_Init(obj->i2c, &obj->sys_cfg, I2CM_SPEED_400KHZ);
  }
  
  //******************************************************************************
  void i2c_frequency(i2c_t *obj, int hz)
  {
      I2CM_Init(obj->i2c, &obj->sys_cfg, (i2cm_speed_t)hz);
  }
  
  //******************************************************************************
  int i2c_start(i2c_t *obj)
  {
      obj->start_pending = 1;
      return 0;
  }
  
  //******************************************************************************
  int i2c_stop(i2c_t *obj)
  {
      obj->start_pending = 0;
      I2CM_WriteTxFifo(obj->i2c, obj->fifo, MXC_S_I2CM_TRANS_TAG_STOP);
      I2CM_TxInProgress(obj->i2c);
      return 0;
  }
  
  //******************************************************************************
  int i2c_read(i2c_t *obj, int address, char *data, int length, int stop)
  {
      return I2CM_Read(obj->i2c, address >> 1, NULL, 0, (uint8_t *)data, length);
  }
  
  //******************************************************************************
  int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop)
  {
      mxc_i2cm_regs_t *i2cm = obj->i2c;
      mxc_i2cm_fifo_regs_t *fifo = obj->fifo;
  
      if (stop) {
          return I2CM_Write(i2cm, address >> 1, NULL, 0, (uint8_t *)data, length);
      }
  
      i2cm->inten = 0;
      i2cm->intfl = i2cm->intfl;
      if (I2CM_Tx(i2cm, fifo, address >> 1, (uint8_t *)data, length, 0) == E_NO_ERROR) {
          return length;
      } else {
          return -1;
      }
  }
  
  //******************************************************************************
  void i2c_reset(i2c_t *obj)
  {
      I2CM_Recover(obj->i2c);
  }
  
  //******************************************************************************
  int i2c_byte_read(i2c_t *obj, int last)
  {
      mxc_i2cm_regs_t *i2cm = obj->i2c;
      mxc_i2cm_fifo_regs_t *fifo = obj->fifo;
      int tmp;
  
      // Start the transaction if it is not currently ongoing
      if (!(i2cm->trans & MXC_F_I2CM_TRANS_TX_IN_PROGRESS)) {
          i2cm->trans |= MXC_F_I2CM_TRANS_TX_START;
      }
  
      if (last) {
          // NACK the last read byte
          if (I2CM_WriteTxFifo(i2cm, fifo, MXC_S_I2CM_TRANS_TAG_RXDATA_NACK) != E_NO_ERROR) {
              goto byte_read_err;
          }
      } else {
          if (I2CM_WriteTxFifo(i2cm, fifo, MXC_S_I2CM_TRANS_TAG_RXDATA_COUNT) != E_NO_ERROR) {
              goto byte_read_err;
          }
      }
  
      do {
          // Wait for data in RX FIFO
          int timeout = MXC_I2CM_RX_TIMEOUT;
          while (!(i2cm->intfl & MXC_F_I2CM_INTFL_RX_FIFO_NOT_EMPTY) &&
                  ((i2cm->bb & MXC_F_I2CM_BB_RX_FIFO_CNT) == 0)) {
  
              if((timeout-- < 0) || (i2cm->trans & MXC_F_I2CM_TRANS_TX_TIMEOUT)) {
                  goto byte_read_err;
              }
  
              if (i2cm->trans & (MXC_F_I2CM_TRANS_TX_LOST_ARBITR | MXC_F_I2CM_TRANS_TX_NACKED)) {
                  goto byte_read_err;
              }
          }
          i2cm->intfl = MXC_F_I2CM_INTFL_RX_FIFO_NOT_EMPTY;
  
      } while ((tmp = fifo->rx) & MXC_S_I2CM_RSTLS_TAG_EMPTY);
  
      return (uint8_t)tmp;
  
  byte_read_err:
      i2c_reset(obj);
      return -1;
  }
  
  //******************************************************************************
  int i2c_byte_write(i2c_t *obj, int data)
  {
      mxc_i2cm_regs_t *i2cm = obj->i2c;
      mxc_i2cm_fifo_regs_t *fifo = obj->fifo;
      int result;
  
      if (obj->start_pending) {
          obj->start_pending = 0;
          data |= MXC_S_I2CM_TRANS_TAG_START;
      } else {
          data |= MXC_S_I2CM_TRANS_TAG_TXDATA_ACK;
      }
  
      if ((result = I2CM_WriteTxFifo(i2cm, fifo, data)) != E_NO_ERROR) {
          i2c_reset(obj);
          if (result == E_COMM_ERR) {
              return MBED_NAK;
          }
          return MBED_TIMEOUT;
      }
  
      // Start the transaction if it is not currently ongoing
      if (!(i2cm->trans & MXC_F_I2CM_TRANS_TX_IN_PROGRESS)) {
          i2cm->trans |= MXC_F_I2CM_TRANS_TX_START;
      }
  
      return MBED_ACK;
  }
  
  const PinMap *i2c_master_sda_pinmap()
  {
      return PinMap_I2C_SDA;
  }
  
  const PinMap *i2c_master_scl_pinmap()
  {
      return PinMap_I2C_SCL;
  }
  
  const PinMap *i2c_slave_sda_pinmap()
  {
      return PinMap_I2C_SDA;
  }
  
  const PinMap *i2c_slave_scl_pinmap()
  {
      return PinMap_I2C_SCL;
  }
  
  #endif  // #if DEVICE_I2C
  